// Copyright 2015 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "src/assembler-inl.h"
#include "src/macro-assembler.h"

#include "src/compiler/linkage.h"

#include "src/zone/zone.h"

namespace v8 {
namespace internal {
    namespace compiler {

        namespace {

// Platform-specific configuration for C calling convention.
#if V8_TARGET_ARCH_IA32
// ===========================================================================
// == ia32 ===================================================================
// ===========================================================================
#define CALLEE_SAVE_REGISTERS esi.bit() | edi.bit() | ebx.bit()

#elif V8_TARGET_ARCH_X64
            // ===========================================================================
            // == x64 ====================================================================
            // ===========================================================================

#ifdef _WIN64
// == x64 windows ============================================================
#define STACK_SHADOW_WORDS 4
#define PARAM_REGISTERS rcx, rdx, r8, r9
#define CALLEE_SAVE_REGISTERS \
    rbx.bit() | rdi.bit() | rsi.bit() | r12.bit() | r13.bit() | r14.bit() | r15.bit()
#define CALLEE_SAVE_FP_REGISTERS \
    (1 << xmm6.code()) | (1 << xmm7.code()) | (1 << xmm8.code()) | (1 << xmm9.code()) | (1 << xmm10.code()) | (1 << xmm11.code()) | (1 << xmm12.code()) | (1 << xmm13.code()) | (1 << xmm14.code()) | (1 << xmm15.code())
#else
// == x64 other ==============================================================
#define PARAM_REGISTERS rdi, rsi, rdx, rcx, r8, r9
#define CALLEE_SAVE_REGISTERS \
    rbx.bit() | r12.bit() | r13.bit() | r14.bit() | r15.bit()
#endif

#elif V8_TARGET_ARCH_ARM
// ===========================================================================
// == arm ====================================================================
// ===========================================================================
#define PARAM_REGISTERS r0, r1, r2, r3
#define CALLEE_SAVE_REGISTERS \
    r4.bit() | r5.bit() | r6.bit() | r7.bit() | r8.bit() | r9.bit() | r10.bit()
#define CALLEE_SAVE_FP_REGISTERS \
    (1 << d8.code()) | (1 << d9.code()) | (1 << d10.code()) | (1 << d11.code()) | (1 << d12.code()) | (1 << d13.code()) | (1 << d14.code()) | (1 << d15.code())

#elif V8_TARGET_ARCH_ARM64
// ===========================================================================
// == arm64 ====================================================================
// ===========================================================================
#define PARAM_REGISTERS x0, x1, x2, x3, x4, x5, x6, x7
#define CALLEE_SAVE_REGISTERS \
    (1 << x19.code()) | (1 << x20.code()) | (1 << x21.code()) | (1 << x22.code()) | (1 << x23.code()) | (1 << x24.code()) | (1 << x25.code()) | (1 << x26.code()) | (1 << x27.code()) | (1 << x28.code()) | (1 << x29.code()) | (1 << x30.code())

#define CALLEE_SAVE_FP_REGISTERS \
    (1 << d8.code()) | (1 << d9.code()) | (1 << d10.code()) | (1 << d11.code()) | (1 << d12.code()) | (1 << d13.code()) | (1 << d14.code()) | (1 << d15.code())

#elif V8_TARGET_ARCH_MIPS
// ===========================================================================
// == mips ===================================================================
// ===========================================================================
#define STACK_SHADOW_WORDS 4
#define PARAM_REGISTERS a0, a1, a2, a3
#define CALLEE_SAVE_REGISTERS \
    s0.bit() | s1.bit() | s2.bit() | s3.bit() | s4.bit() | s5.bit() | s6.bit() | s7.bit()
#define CALLEE_SAVE_FP_REGISTERS \
    f20.bit() | f22.bit() | f24.bit() | f26.bit() | f28.bit() | f30.bit()

#elif V8_TARGET_ARCH_MIPS64
// ===========================================================================
// == mips64 =================================================================
// ===========================================================================
#define PARAM_REGISTERS a0, a1, a2, a3, a4, a5, a6, a7
#define CALLEE_SAVE_REGISTERS \
    s0.bit() | s1.bit() | s2.bit() | s3.bit() | s4.bit() | s5.bit() | s6.bit() | s7.bit()
#define CALLEE_SAVE_FP_REGISTERS \
    f20.bit() | f22.bit() | f24.bit() | f26.bit() | f28.bit() | f30.bit()

#elif V8_TARGET_ARCH_PPC64
// ===========================================================================
// == ppc & ppc64 ============================================================
// ===========================================================================
#ifdef V8_TARGET_LITTLE_ENDIAN // ppc64le linux
#define STACK_SHADOW_WORDS 12
#else // AIX
#define STACK_SHADOW_WORDS 14
#endif
#define PARAM_REGISTERS r3, r4, r5, r6, r7, r8, r9, r10
#define CALLEE_SAVE_REGISTERS \
    r14.bit() | r15.bit() | r16.bit() | r17.bit() | r18.bit() | r19.bit() | r20.bit() | r21.bit() | r22.bit() | r23.bit() | r24.bit() | r25.bit() | r26.bit() | r27.bit() | r28.bit() | r29.bit() | r30.bit()
#define CALLEE_SAVE_FP_REGISTERS \
    d14.bit() | d15.bit() | d16.bit() | d17.bit() | d18.bit() | d19.bit() | d20.bit() | d21.bit() | d22.bit() | d23.bit() | d24.bit() | d25.bit() | d26.bit() | d27.bit() | d28.bit() | d29.bit() | d30.bit() | d31.bit()

#elif V8_TARGET_ARCH_S390X
// ===========================================================================
// == s390x ==================================================================
// ===========================================================================
#define STACK_SHADOW_WORDS 20
#define PARAM_REGISTERS r2, r3, r4, r5, r6
#define CALLEE_SAVE_REGISTERS \
    r6.bit() | r7.bit() | r8.bit() | r9.bit() | r10.bit() | ip.bit() | r13.bit()
#define CALLEE_SAVE_FP_REGISTERS \
    d8.bit() | d9.bit() | d10.bit() | d11.bit() | d12.bit() | d13.bit() | d14.bit() | d15.bit()

#else
// ===========================================================================
// == unknown ================================================================
// ===========================================================================
#define UNSUPPORTED_C_LINKAGE 1
#endif
        } // namespace

        // General code uses the above configuration data.
        CallDescriptor* Linkage::GetSimplifiedCDescriptor(
            Zone* zone, const MachineSignature* msig, bool set_initialize_root_flag)
        {
            DCHECK_LE(msig->parameter_count(), static_cast<size_t>(kMaxCParameters));

            LocationSignature::Builder locations(zone, msig->return_count(),
                msig->parameter_count());
            // Check the types of the signature.
            // Currently no floating point parameters or returns are allowed because
            // on ia32, the FP top of stack is involved.
            for (size_t i = 0; i < msig->return_count(); i++) {
                MachineRepresentation rep = msig->GetReturn(i).representation();
                CHECK_NE(MachineRepresentation::kFloat32, rep);
                CHECK_NE(MachineRepresentation::kFloat64, rep);
            }
            for (size_t i = 0; i < msig->parameter_count(); i++) {
                MachineRepresentation rep = msig->GetParam(i).representation();
                CHECK_NE(MachineRepresentation::kFloat32, rep);
                CHECK_NE(MachineRepresentation::kFloat64, rep);
            }

#ifdef UNSUPPORTED_C_LINKAGE
            // This method should not be called on unknown architectures.
            FATAL("requested C call descriptor on unsupported architecture");
            return nullptr;
#endif

            // Add return location(s).
            CHECK_GE(2, locations.return_count_);

            if (locations.return_count_ > 0) {
                locations.AddReturn(LinkageLocation::ForRegister(kReturnRegister0.code(),
                    msig->GetReturn(0)));
            }
            if (locations.return_count_ > 1) {
                locations.AddReturn(LinkageLocation::ForRegister(kReturnRegister1.code(),
                    msig->GetReturn(1)));
            }

            const int parameter_count = static_cast<int>(msig->parameter_count());

#ifdef PARAM_REGISTERS
            const v8::internal::Register kParamRegisters[] = { PARAM_REGISTERS };
            const int kParamRegisterCount = static_cast<int>(arraysize(kParamRegisters));
#else
            const v8::internal::Register* kParamRegisters = nullptr;
            const int kParamRegisterCount = 0;
#endif

#ifdef STACK_SHADOW_WORDS
            int stack_offset = STACK_SHADOW_WORDS;
#else
            int stack_offset = 0;
#endif
            // Add register and/or stack parameter(s).
            for (int i = 0; i < parameter_count; i++) {
                if (i < kParamRegisterCount) {
                    locations.AddParam(LinkageLocation::ForRegister(kParamRegisters[i].code(),
                        msig->GetParam(i)));
                } else {
                    locations.AddParam(LinkageLocation::ForCallerFrameSlot(
                        -1 - stack_offset, msig->GetParam(i)));
                    stack_offset++;
                }
            }

#ifdef CALLEE_SAVE_REGISTERS
            const RegList kCalleeSaveRegisters = CALLEE_SAVE_REGISTERS;
#else
            const RegList kCalleeSaveRegisters = 0;
#endif

#ifdef CALLEE_SAVE_FP_REGISTERS
            const RegList kCalleeSaveFPRegisters = CALLEE_SAVE_FP_REGISTERS;
#else
            const RegList kCalleeSaveFPRegisters = 0;
#endif

            // The target for C calls is always an address (i.e. machine pointer).
            MachineType target_type = MachineType::Pointer();
            LinkageLocation target_loc = LinkageLocation::ForAnyRegister(target_type);
            CallDescriptor::Flags flags = CallDescriptor::kNoFlags;
            if (set_initialize_root_flag) {
                flags |= CallDescriptor::kInitializeRootRegister;
            }

            return new (zone) CallDescriptor( // --
                CallDescriptor::kCallAddress, // kind
                target_type, // target MachineType
                target_loc, // target location
                locations.Build(), // location_sig
                0, // stack_parameter_count
                Operator::kNoThrow, // properties
                kCalleeSaveRegisters, // callee-saved registers
                kCalleeSaveFPRegisters, // callee-saved fp regs
                flags, "c-call");
        }

    } // namespace compiler
} // namespace internal
} // namespace v8
